1. Field of the Invention
The present invention relates to a self-centering timing disk hub with a timing disk support surface (1a) and a tubular hub sleeve (1b) and to a method for mounting the same on a motor shaft.
2. Description of the Related Art
Self-centering timing disks of the afore described type are known from DE 196 41 929 A1 (RUHLATEC Industrieprodukte GmbH). The timing disk hub described therein is installed in an encoder which is connected with a motor by a simple rotational motion.
Sufficient clearance should be provided for centering the timing disk hub on the motor shaft during installation. For this reason, the end of the timing disk hub facing the motor has a pilot bore for aligning the vertical axes of the shaft and the timing disk. With current state-of-the-art devices, a distortion tended to occur when the shaft is inserted into the timing disk hub, since the hub which is pushed onto the finish-machined shaft, has a reduced diameter. A housing surface exerts an axial pressure on the timing disk support surface, thereby moving the timing disk support surface and the timing disk hub connected thereto into the proper position for a centered placement in the encoder housing.
Such timing disks are used in an increasing number of applications and produced in large quantities. The stringent requirements on the surface quality of the motor shaft and the timing disk hub as well as the tight manufacturing tolerances create a cost pressure in mass production. It is also difficult to maintain the required tolerances in production. A slight displacement of the timing disk relative to the motor shaft can adversely affect the operation of, for example, servo motors. Manufacturing tolerances can have a significant effect due to the large forces applied during the pressing process.